PHYSICS 2nd Year MCQs Chapter No.4 ELECTROMAGNETIC INDUCTION Test No.1

Alternating emf is produced by rotating a rectangular coil of wire in

A.C current reverses its direction

In D.C. generator, output of every coil is tapped only as it reaches its

If the number of turns and the length of an inductor is doubled, then inductance(L) becomes

The maximum emf produced by an alternating generator is

The energy stored in an inductor is given by

A motor of zero back emf draws ---- current

The inductance in a coil plays the same role in AC circuits as in ----- play in mechanics

The SI unit of self-inductance is

The value, of the induced emf in a loop of wire is directly proportional to the rate of change of ------ through the loop

The direction of the induced current in a certain coil can easily be found by using

If a steady current is passing though a coil then the self induced emf in it will be

If N is the number of turns in a coil, the value of self-inductance varies as

Current can be induced in a coil by changing the area of the coil in a

An inductor may store energy in

If the plane of A.C. generator coil is parallel to the field, then emf induced or current in coil is

The fluctuations of the output of generator can be reduced by

An induced emf is produced in a circuit when

Alternating current generator uses

The motional emf in a conductor can be increased by

Which one of the following expressions for mutual inductance is correct

The phenomena by which an induced emf is produced due to change of flux is called

Lenz's law deals directly with the

SI unit of mutual inductance is

The ratio of average emf in the coil to the time rate of change of current in the same coil is called

The emf induced by the motion of a conductor across a magnetic field is called

The working of A.C. generator is based upon the phenomenon of

The back emf of a motor can be expressed as

The induced emf in a rotating coil of A.C. generator varies with time

In mutual induction, the coil placed with source of electric energy is called

The mathematical expression for self-inductance of coil is given by

The number of coils wound around an iron cylinder and rotated in magnetic field is called

In alternating current, inductors behaves like

Motional emf does not depend upon

The most common source of an A.C. voltage is

The mutual inductance of two coils is given by the relation

The only difference between construction of D.C. generator and an A.C. generator is that of

Back motor effect in generators is in accordance with law of conservation of

The self inductance of the coil depends upon

Energy stored per unit volume inside the solenoid is called

Mutual inductance has a practical role in the performance of the

In motional emf experiment when the system reaches an equilibrium state

If the coil is wound on an iron core, the flux through it will

If the length of a conductor placed parallel to magnetic field is doubled, the induced emf

One henry is equal to

When a motor car is started its head light first becomes slight dim because the voltage across the lamp

The principle of an electric generator is based on

The self inductance of a coil ---- when a soft iron is placed into it

The mutual inductance of coils depends upon

The motional emf of a conductor of length L and moving perpendicular to a magnetic field B is equal to

When current flows through the armature coil, the force on the conductor produces

If back emf in a motor decreases, then it will draw

The device in the circuit that consumes electrical energy is called

A motor is a device which converts electrical energy into

It is the converse process of magnetic effect of current

The device which is used to increase or decrease the value of alternating voltage is called

A generator running in reverse may be called as

Faraday law is given by

Commutator was invented in

In case of alternating current, the average value of current and voltage is

If the plane of A.C. generator coil is perpendicular to the field, then emf induced or current in coil is

The induced emf lasts so long as the magnetic flux keeps

The emf induced in the coil of A.C. generator will be maximum when the angle between the plane of coil and the magnetic field is

The, phenomenon of induced emf was observed by Faraday and Henry in

A metallic ring is attached to wall of a room When the north pole of bar magnet is brought near the ring, the induced current in the ring is

Faraday's law is based upon law of conservation of

If a conductor of length 1 m is moved with velocity V across a magnetic field B at an angle of 30° with B ,then motional emf will be

The amount of torque in D.C. motors, depends upon

A device which converts mechanical energy into electrical energy is called

The current flowing through a coil due to induced emf hi it depends upon

The induced emf in a motor which opposes the applied emf running the motor is called

weber / ampere is the 'unit of

△Φ/△t has the same unit as that of

When a motor is over loaded; then the magnitude of back emf

The working of electric motor is reversed of

If a conductor is placed perpendicular to a magnetic field B is then motional emf will be

Lenz's law is in accordance With the law Of conservation of

Self inductance (L) of a coil is

The self-inductance of the coil is given by

Commutator was invented by

The ratio Of the emf induced in the secondary coil to the rate of change of current in the primary coil is known as

The phenomenon in which changing current in a coil induces an emf in itself is called

In self induction phenomenon, the total flux through the coil is directly proportional to the ----- through the coil

Induced current always acts to ------- the magnetic flux through the circuit

When motor is started, the back emf is

The fact that emf produced by motion of a coil across a magnetic field was discovered by

The coil used to obtain the output by mutual induction phenomenon is known as

1 VsA^-1 =

The component mainly used in a D.C. generator is